The use of mobile communications networks has increased over the last decade. Operators of the mobile communications networks have increased the number of base transceiver stations in order to meet an increased demand for service by users of the mobile communications networks. Scarcity of available frequencies has always been an issue. Frequencies have to be re-used in other cells. A certain distance between cells using the same frequency in some mobile communications protocols has to be kept in mind to avoid interference between radio signals being transceived, which decreases signal quality.
One way of improving the signal quality is to use steered adaptive antenna systems in which individual ones (or groups) of subscriber devices are tracked both in azimuth and elevation. In other words, a radio beam from the adaptive antenna systems of the art tries to follow the subscriber devices and concentrates the power of the radio beam on the tracked ones of the subscriber devices. This tracking requires quite a lot of hardware and software resources and may furthermore lead to other ones of the subscriber devices, for example situated at the edge of a coverage area, being “ignored” by the adaptive antenna system leading to a reduction in quality of the radio signal and even to non-reachability or dropping of a call.
The term “base transceiver station (BTS)” in the context of this disclosure includes, but is not limited to, base stations, as known from GSM networks, as well as a node B (known from UMTS/3G networks) or enhanced node B, and similar units used in other mobile communication network.
The term “subscriber device” in the context of this disclosure is intended to encompass all types of mobile stations and other devices connected to the mobile communication network. Such subscriber devices can be portable or stationary. For example wireless modules can be incorporated into vending machines for the transceiving of data over the mobile communication network. Such wireless modules are also considered to be subscriber devices.